These easiest way is to work with .zip files instead of .7z and use Dot Net Zip
When spinning off 7zip commands to shell there are other issues like user privileges, I had issue with SevenZipSharp.
Private Function CompressFile(filename As String) As Boolean
Using zip As New ZipFile()
zip.AddFile(filename & ".txt", "")
zip.Save(filename & ".zip")
End Using
Return File.Exists(filename & ".zip")
End Function